The trend in the disk drive industry over the past several years has been to scale down the size or form factor of the package housing the disk drive assembly. For example, shrinking form factors have reduced the size of disks from 5.25" down to 3.5", 2.5", 1.8" and 1.3" diameters in recent years. At the same time, advances in recording technology have increased track density so as to achieve increased data storage capacity, despite the reduction in form factor size.
Much of the reduction in the size of the disk drive assembly unit has been brought about by simply shrinking the dimensions of the various components. For example, by reducing the size of the spindle motor, the actuator bearings, the disk diameter and the surrounding enclosure the size of data storage units has been reduced dramatically. Another way that size has been reduced-particularly in the vertical (i.e., height) dimension has been by reducing the number of disks mounted to the spindle motor. In other words, eliminating many of the of disks, within the enclosure, has allowed a corresponding reduction in the height or thickness of the disk storage unit. However, to further reduce the overall size beyond current limits--and especially to reduce the thickness of the disk storage unit--a radical new approach to the design and integration of the components which make up the drive is required.
In conjunction with the trend toward reducing the size of disk storage units, there has also been a corresponding trend in the computer industry toward creating ever more portable computing resources. For instance, many modern computer systems manufactured today have the capability of providing standard connections to removable memory cards. To further advance this technology, the Personal Computer Memory Card International Association (PCMCIA) has adopted certain connector dimensions, interfaces, and configurations as standards for the computer industry. In this respect, PCMCIA compatible solid-state memory cards are manufactured to have certain outside dimensions and connector configurations which allow installation into a standard PCMCIA interface with a host computer. Currently, there are three types of PCMCIA standard card sizes: The Type III card which has a vertical thickness of 10.5 mm, the Type II card, which has a thickness of 5.0 mm, and the Type I card which is 3.3 mm thick. The length and width of a PCMCIA memory card are also rigidly defined by the PCMCIA standards.
What is desirable then, and what the present invention achieves, is a disk storage unit packaged in a PCMCIA compatible memory card. The invention involves packaging of a 1.3" disk drive in an enclosure which has the same dimensions as a PCMCIA memory card of the Type I, Type II, or Type III dimension. A host computer can communicate with the disk storage unit of the present invention using a standard PCMCIA interface. In the past, previous hard disk drive units have not offered removability and portability in such a small package. Thus, the packaging of a disk drive unit in the PCMCIA card provides removable and portable high capacity data storage at a relatively low cost. As will be seen, the accomplishment of PCMCIA compatible dimensions for a disk storage unit are made possible by advances in the design of the internal disk drive assembly components, and in the packaging of the drive together with the electronic circuits used in controlling the reading and writing of information to the disk.